Cell Cycle Phases Flashcards
The Cell Cycle consists of
Interphase + Mitosis
Interphase pertains to
Cell growth (no division)
Most cells are found in which phase of the cycle?
Interphase
What are the parts of interphase?
- G1
- S
- G2
G1 is the growth phase which is also the
Longest phase
What happens during the G1 phase?
Extra organelles like ribosomes + proteins are produced
After G1, cells can go to either
G0 or S
Which cyclins are produced during G1?
CycE or CycD
S Phase is the Synthesis phase in which there is
DNA replication of 23 pairs
Which cyclins are produced during S phase?
Cyclin A, which binds with CDK to activate DNA replication
G2 is the growth phase in which the cell
Prepares for mitosis
What happens during the G2 phase?
Microtubules are made
Which cyclins are produced during G2 phase?
Cyclin B to bond with CDK 1
The first checkpoint is found between
G1 and S phase
DNA replication is not inhibited when
CDK binds to the Cyclins E and D
Second checkpoint is found between
G2 and mitosis
CDK gets activated when paired with
Cyclins
What is required in order to pass checkpoints?
Cyclin proteins need to present to block any proteins which may interfere with DNA synthesis or replication
PB3 is a protein that functions to
Block cell cycle progression
P21 is a protein that
Inhibits CDK
Rb + P53 are tumor-suppressor genes, so a defect can result in
Cancer
Most of the cell’s life and DNA replication occurs during
Interphase
How are chromosomes in interphase?
Not tightly bound, rather in chromatin form
